I am feeling like I am in a bit of a sticky moral situation and unsure what to do - the reason I am unsure is because I am a little worried about potential female to male emotional abuse in this relationship; I would normally stay the hell away from things like this as you never know the boundaries of other people's relationships.
I know someone, a female, from university who has always had quite a high sex drive - this cause quite a lot of issues during our three years at university, but I remained friends with her afterwards. Very few people did. She never slept with my partner, but did sleep with others, and would often, usually when drunk, say things like "Oh, a wedding ring, what a challenge".
It was more of an acquaintance than a friendship at first, but a few years later she started visiting where I lived (big city). She had a partner at home and it was looking serious. At first the pretence was "It's a big city and I'm too scared to stay in a hotel on my own". It then became obvious she was coming down and staying with someone else in hotels and using me as a cover; I was asked outright to lie to her partner about it which I refused to do.
She immediately started saying how difficult her partner was and how she had had to make him delete all his social media because he was the "jealous type"; I felt pretty shit for her and gave her advice red flags in relationships. The next day she confided that she'd been screwing around with two different men and she really needed me to lie to save her relationship.
Again, I said no. That was pretty much the last time we spoke bar some messages from her when she's been drunk about what a bitch I am, how her partner is really ill and I have not been supportive and a couple saying she needed someplace to stay. Then a few more with a load of abuse when I ignored them - eventually I blocked her number.
Her partner has just proposed. I know that she's still screwing one of the men because she's now using another mutual friend as a "cover" for her "work trips away". I haven't said anything to the mutual friend and don't actually know if she knows she's being used to cover up behaviour. However, mutual friend was telling me that she was worried about the level of control in the relationship - the guy not being allowed social media, control of finances, and, constantly being accused of being "psycho" when he raises concerns about his partner's potential cheating.
I really want to contact him and tell him he's not a psycho, he's totally on the right track and he needs to get the hell away from her. AIBU?